The Bypass Angioplasty Revascularization Investigation (BARI) is a randomized clinical trial to compare the relative efficacy of an initial strategy of PTCA versus CABG in patients with multivessel coronary disease and severe angina or ischemia. Treatment strategies will be compared with respect to clinical outcome and economic impact. The trial was initiated in 1987 and investigators from 14 primary sites and 5 satellites have randomized 1829 patients. Of these, 43% are elderly, 27% are female, and 6% are black. BARI patients are at high risk for cardiac events; 55% presented with a history of myocardial infarction, and 69% with unstable angina or non Q-wave MI. At baseline, triple-vessel disease was present in 41% and 73% had three or more significant lesions (greater than ore equal to 50% stenosis). As of July 1993, the first patient randomized will have been followed for 5-years and the last patient will have been followed for 2 years. In addition to the randomized trial, BARI contains a registry comprised of 2013 eligible-not-randomized and registry patients, we propose to complete and report 5-year follow-up results and extend follow-up to 10 years. In randomized patients, treatment strategies will be compared with respect to mortality, myocardial infarction, need for repeat procedures and.hospitalizations, functional status, radionuclide ejection fraction and quality of life. Periprocedural outcome will also be reported. Similar analyses will be reported for both registry groups. To accomplish 10-year follow-up, we will use the same methods of data collection and management, and continue the same lines of communication between the clinical sites, central laboratories and the NHLBI that have served BARI successfully to this point. The clinical sites will rely on the excellent long-term relationships established with their patients and referring physicians. Ten-year follow-up results will provide the long-term cost of PTCA versus CABG, not only in terms of dollar expenditures but in terms of quality of life, morbidity and longevity. The results of BARI will have an important impact on the future practice of coronary revascularization and thus affect hundreds of thousands of patients who are expected to undergo these procedures.